I have a PC running windows XP that has 4 x 1GB memory chips but when you run System from the control panel it states that I only have 3GB or ram. If you go into the bios it states all 4 slots are occupied.

What are my options is it that one of the chips is defective or is it a quirk of windows. Are their any free apps that I can run in windows to check the memory.

It is a CAD PC that really needs more memory but right now I am to busy to change over to a new PC as it would mean upgrading from XP and theirfore lots of other software might not work which is a chance I can’t afford to take right now.

Cougar will be along shortly to explain it properly, but basically you can’t have more than 3GB in XP

You need a 64bit operating system for 4GB.

You have a 32bit OS which can only handle 3GB of memory no matter how much is installed.

Upgrade to 64Bit Win 7 and you’ll be sorted!! Edit – Too late

As above, XP limited (in essence) to 3 (and a bit).

Strictly speaking, as mentioned above, its a limitation of 32bt operating systems. You can get a 64bit version of XP

I new XP was limited I thought it was limited to 4GB not 3 so that clears that up. Am I affecting perfromance by having 4GB installed should I remove 1GB, something in the depth of my brain says you have to install ram in pairs.

Don’t get XP 64 it’s awful and poorly supported as is Vista 64.

32bit operating systems run out of numbers used to address the memory at 4GB. Because some of the devices on your computer also take up some of these numbers, there aren’t enough to allow you to “see” all 4GB.

Your memory will be working at it’s appropriate speed etc. it’s just that Windows has no way of addressing it, and therefore using it.

You should be able to get XP to see all 4 gig – see here
http://msdn.microsoft.com/en-us/windows/hardware/gg487503.aspx

Better still just move to 7 🙂

It’ll be fine running at 4gb. My laptop runs 4gb, buts sees only 3gb. It makes it much faster especially if photo or video editing or other hungry programs

You can address more than 4GB of RAM with a 32bit OS.

http://www.geoffchappell.com/viewer.htm?doc=notes/windows/license/memory.htm

😉

Cougar will be along shortly to explain it properly, but basically you can’t have more than 3GB in XP

The short answer is, that’s the way it is, leave it alone. Anyone suggesting that you need to move to x64 to use the ‘lost’ memory is missing the point; whilst it’s technically correct, it’s as nonsensical in practical terms as suggesting that you run more programs because your CPU usage is only running at 10%.

There are many good reasons for moving to x64. This is not one of them. Enjoy your PC and stop worrying about it.

I new XP was limited I thought it was limited to 4GB not 3 so that clears that up.

It is, that’s not really what’s happening. You’re limited to 4Gb, but some of that 4Gb is inaccessible due to other devices needing to use the same address space. It’s a quirk of the architecture.

Am I affecting perfromance by having 4GB installed should I remove 1GB, something in the depth of my brain says you have to install ram in pairs.

No. Again, this isn’t a short answer and is dependent on how your PC’s set up, but if you install DIMMs in pairs you may well be operating in “dual channel” mode, which is faster. This is unrelated to Windows or to your OP, but my advice is as before, leave it alone. (-:

You can address more than 4GB of RAM with a 32bit OS.

That’s hilarious.

My pc is fine but it is running solidworks and crashes with run out of memory errors when running big models of assemblies. Its an old version of solidworks so wont run on windows 7. As I haven’t kept up the subscriptions solidworks don’t wont to know. Just thought i would ask.

Forgot to say thanks for all the help.

Yeah, see, in an ideal world what you’d need there is an x64 flavour of Windows and an x64 version of Solidworks. Which sounds expensive to me.

If it’s actually out of memory, you might improve your lot by increasing the size of the page file. You might not, but it’s worth a punt.

There are x64 and x32 versions of solidworks available, which version are you running currently ?

I place big money that he’s running x32 on an XP system.

Don’t get XP 64 it’s awful and poorly supported as is Vista 64.

Well, I’ve had vista64 for about 3 years now – never had a peep out of it…

32bit OS with PAE can use more than 4GB of ram.

Got a Redhat AS server at work – 32bit – with 16GB of ram.